Just months before a trove of Democratic National Committee emails were hacked and published online, a DNC communications director mocked a BuzzFeed News report in May that questioned the effectiveness of its cybersecurity.

Buried in the trove was one email from deputy communications director Eric Walker sent to what appeared to be a broad communications team mailing list on May 5. The email shared a BuzzFeed News report, published on the same day, in which cybersecurity experts questioned the online security of both the Democratic and Republican national committees.

"The dumbest thing I've ever read: Buzzfeed: These Experts Think The DNC And RNC Are Both Horrible At Cybersecurity," Walker wrote in the subject line, referencing the title of the story.

BuzzFeed News

The article, by cybersecurity correspondent Sheera Frenkel, featured quotes from analysts who critiqued both parties for handing out thumb drives to reporters.

"Thumb drives are known within the cybersecurity world for their fundamental security weaknesses," Frenkel wrote, "because when someone plugs a thumb drive into their computers they are opening up their system to anything on that drive — from the best hotels to stay in during the Republican National Convention to a virus that silently uploads itself onto the hard drive."

“Those thumb drives are the number one way to infect a computer," Ajay Arora, CEO of cybersecurity firm VERA, told Frenkel. "It is borderline stupidity to give them out to people, or for people to even think of using them.”

In addition to describing it as "the dumbest thing [he had] ever read," Walker derided the "thesis" of the story.

"The thesis: we hand out thumb drives at events, which could infect the reporters/attendees' computers. So that means that we're bad at cybersecurity. Okay," he wrote.

Walker did not immediately respond to requests for comment on Saturday.

Wikileaks has not revealed the source of the leak, but the DNC said in June it had been breached by Russian hackers. It is not known if the hackers relied on thumb drives in order to breach the DNC's cybersecurity.